Primary hyperoxaluria is a rare inherited disorder that results from a deficiency of D-glycerate dehydrogenase activity in the liver. The elevated urinary oxalate excretion that occurs in this disease can result in kidney failure and premature death due to the tissue deposition of calcium oxalate crystals. Our long-term objectives are to identify the genetic changes that cause the disease, develop techniques for its rapid and accurate diagnosis, to understand the physiological role of D-glycerate dehydrogenase, and to design therapies to treat the disease. The specific aims of this proposal are to (1) determine the nucleotide sequence, structure, and chromosomal location of the gene coding for D-glycerate dehydrogenase, (2) identify mutations in the gene of individuals with primary hyperoxaluria type 2 and develop PCR methods to detect these mutations, (3) produce and purify a recombinant form of the enzyme, (4) determine the tissue expression and intracellular localization of DGDH, and (5) examine the properties of the recombinant DGDH. To make this research possible the cDNA for the human D-glycerate dehydrogenase gene has been sequenced and shown to encode for the enzyme by transfection assays in COS cells. Molecular biology techniques will be utilized to obtain the complete sequence of the gene, to identify the changes that occur in the genes of individuals with the disease, and to obtain recombinant protein. The chromosomal location of the gene will be determined using fluorescent in situ hybridization techniques. The proposed research should greatly enhance our understanding of the cause of the disease, will assist in the development of treatments and diagnoses for the disease, and will facilitate our understanding of the physiological functions of the enzyme.